THE SEA-FLIERS. 215 



weather. All day long they are occupied in flying over the waves, the risings and fallings of which 



they exactly follow, or in mounting high in the air like Swallows, whence they descend again, as though 



about to plunge into the water, but rise again without touching it. Sometimes again they settle down 



upon the water, and remain motionless, as if unable to move from the same spot, though all around 



them is in constant agitation and turmoil. When flying they make but few strokes with their wings, 



but these are obviously very effective, and their action much diversified. Sometimes they may be 



seen with their wings widely expanded, and in this manner they sail along for minutes together, 



without the slightest effort, then, suddenly bestirring themselves, a few quick powerful strokes given 



after the manner of a Swift, raise them above the waves, where they astonish the observer by the 



masterly precision of their evolutions, as they shoot down obliquely over the billows, or mount up 



again high into the air. Should they espy anything in the shape of food, they at once hasten towards 



it, running upon the water, and, having seized it with their beak, immediately resume their aerial 



pastime. As to their powers of swimming, they seem so seldom to adopt that mode of locomotion, 



that many careful observers declare that they never swim at all, but that they only sit down, as it 



were, and float on the sea, without ever using their legs as instruments of propulsion. Their strength 



of wing is wonderful ; they literally fly about all day long without resting at all. It is only after the 



long continuance of a storm that they seem to be wearied, and yet even this fatigue is not produced 



by their exertions in battling with the wind, but because, during the violence of the tempest, they are 



unable to obtain their usual supply of food, and consequently are exhausted for want of nourishment. 



Their voice is seldom heard in the daytime, which in truth appears to be to them the season of 



repose ; it is in the evening, shortly after the sun has gone down, that they seem most active and 



alert ; at that time, should the wind permit, their call-note may be frequently heard. In disposition 



they are particularly harmless, living in perfect good-fellowship with each other, and appearing to care 



little about other birds. Their food consists of all sorts of soft-bodied animals, picked up from the 



surface of the ocean; but we are unable to say more upon this subject. The stomachs of such as have 



been examined invariably contained nothing but a fluid resembling train-oil, but never the slightest 



trace of animal remains. 



THE COMMON STORM PETREL. 



The Common Storm Petrel (Thalassidroma pelagica) has the end of the tail very slightly 

 rounded. The general colour of this species is a sooty brown ; the upper part of the head is of a 

 glossy black, becoming browner towards the forehead, and the mantle blackish brown. The 

 wing-covers have white points, and the rump is likewise white. The eye is brown, beak black, and 

 foot reddish brown. This species is five inches and a quarter long, and twelve inches and a half 

 broad ; the length of the wing is four inches and a half, and tail two inches. The Storm Petrel, 

 though not generally distributed over the coast of Great Britain, is indigenous, breeding in Shetland, 

 the Orkneys, and the islets on the Irish coast. During severe gales individuals have been shot as 

 far inland as Berks, Warwickshire, and Derbyshire. 



Mr. Hewitson gives the following account of the breeding of the Petrels in Shetland: — 

 " On the 31st May these birds had not arrived on the breeding-ground ; to use the the phrase of the 

 fishermen, ' Had not yet come up from the sea.' Some eggs were deposited as late as the 30th June. 

 In Foula they breed in the holes in the cliff at a great height above the sea ; but here (in 

 Oxna) under stones which form the beach, at a depth of three or four feet or more, according to that 

 of the stones, as they go down to the earth beneath them, on which to lay their eggs. In walking 

 over the surface I could hear them very distinctly singing in a sort of a warbling chitter, a good deal 

 like Swallows, when fluttering above our chimneys, but harsher ; and in this way, by listening 

 attentively, was guided to their retreat ; and, after throwing out stones as large as I could lift on all 



